Prototyping is a crucial step that may seem tedious but its almost always mandatory and will save you a lot of money and time.
Understand that your prototypes aren't going to be perfect on the first try and that's why you make prtotypes.
When adding or Redoing features in a model, make sure that your parametric timeline doesn't break
When you accidentally made a wrong hole or made a part too small, do not be discouraged but use it as fuel to make your next prototype even better until you are comfortable with your final prototype and then you can go to the next step.